Chemical lasers operate by directing one or more suitably energized specie(s) through an optical cavity. The optical cavity extracts energy, above some threshold value, from the stream of energized specie(s) and combines it into a single coherent beam, which is then removed from the optical cavity in some manner.
Gaseous molecules such as oxygen are capable of existing in different energy states. A gaseous molecule is considered to be an excited state when its energy is higher than its usual ground state energy level. The excited state for oxygen, denoted the singlet delta state, possesses approximately 1 eV (electron-volt) of energy greater than its ground state. Consequently, O.sub.2 (.sup.1 .DELTA.) can serve as an energizing gas and a source of pumping in a high energy chemical laser.
In a chemical oxygen iodine laser, for example, the energized species is predominantly (99%) molecular oxygen in the first electronically excited (singlet delta) state. The remainder of the energy (1%) is contained in the lasing species; atomic iodine which is produced automatically when a small amount (0.5%) of molecular iodine is added to a flow of excited oxygen. Substantially all the energy generated by the laser is originally that stored in the molecular oxygen. Thus, an apparatus capable of producing large amounts of excited oxygen is usually needed to run such a laser at the highest levels of power and efficiency.
Because a primary method of producing singlet delta oxygen for chemical lasers involves the reaction of chlorine gas with a liquid mixture of sodium or potassium hydroxide and hydrogen peroxide, it is desirable for an apparatus to generate excited oxygen atoms to provide: (1) a high interfacial surface area for reaction, (2) a method of separating the chlorine gas from the liquid mixture at the completion of the reaction, and (3) a method for cooling the reaction liquid which heats up during the course of producing singlet delta oxygen. (The heating of the liquid produces water vapor, hydrogen peroxide vapor, and other species which can reduce the efficiency and power of the chemical oxygen iodine laser.)
Chemical generation of O.sub.2 (.sup.1 .DELTA.) has been accomplished heretofore by resorting to a variety of methods. These methods, however, were not capable of producing the energizing gas at high enough pressures or with the necessary low vapor concentration in amounts adequate to satisfy the needs of very low weight, highly efficient, chemically pumped high energy lasers.
As previously discussed, the generation of excited molecular oxygen in the singlet delta electronic state is often required to power a chemical laser as well as to provide a stable, gaseous source of an energetic species for chemical laser applications. Current generators of singlet delta molecular oxygen:
1. Usually do not operate particularly well at high pressures (&gt;30 Torr). PA1 2. Normally require external purification of the generated oxygen stream to remove unwanted water and peroxide vapor. PA1 3. Often require high pressure and high flow rate liquid recirculating systems. PA1 4. Can produce undesirable liquid droplets within the flow of molecular oxygen. PA1 1. Providing a device for generating an adequate supply of an electronically excited gas for use as an energizing medium in a chemical laser. PA1 2. Providing a simple device for generating molecular oxygen in the excited singlet delta state. PA1 3. Providing a simple device which allows for direct cooling of the chemical reaction zone during the generation of an electronically excited gas. PA1 4. Providing a simple device which produces oxygen in the singlet delta electronically excited state in all orientations relative to gravity as well as in zero gravity conditions.
This invention relates to high energy chemical lasers and to a device for generating singlet delta oxygen for use with such lasers. More particularly, the invention relates to a simple and dependable apparatus for generating cold, dry molecular oxygen in the singlet delta state--identified by the symbol O.sub.2 (.sup.1 .DELTA.)--substantially free from the contaminations usually present in such flows.